The 25-year-old right-back, who was not in the preliminary 26-man list announced by Advocaat two weeks ago, was added to the final roster after the Russians lost two defenders, Vasily Berezutsky and Roman Shishkin, to injury and illness.
"We had to call up Nababkin because we were short in defence," Advocaat told reporters.
"In case something happens to our starting right-back Alexander Anyukov he [Nababkin] could give us some cover."
Russia, who face Euro 2012 co-hosts Poland, 2004 European champions Greece and Czech Republic in Group A, now have six defenders, although wingers Yuri Zhirkov and Dmitry Kombarov can also help out at the back if needed.
Advocaat also axed two debutants, midfielder Magomed Ozdoyev and striker Artem Dzyuba, from the preliminary squad to make room for Nababkin, who has had some Champions League experience playing for his club.
"We had to have a balanced squad with enough defenders, midfielders and attackers," said the Dutchman, who will step down as Russia boss following the tournament to take charge of Dutch club PSV Eindhoven.
"As for Nababkin, I've seen him play for CSKA. He has enough international experience."
Earlier this month, Advocaat dropped experienced midfielders Diniyar Bilyaletdinov and Vladimir Bystrov from the preliminary squad, preferring to call up newcomer Alexander Kokorin instead.
Captain Andrei Arshavin and striker Roman Pavlyuchenko, who excelled at Euro 2008 where the Russians reached the semi-finals but have struggled to regain their top form this season, were also included in the final roster.
Sporting midfielder Marat Izmailov, who had not played for the national team since 2006, also made the final cut.
Squad:
Goalkeepers: Igor Akinfeyev (CSKA Moscow), Vyacheslav Malafeyev (Zenit St Petersburg), Anton Shunin (Dynamo Moscow).
Defenders: Alexander Anyukov (Zenit St Petersburg), Alexei Berezutsky (CSKA Moscow), Sergei Ignashevich (CSKA Moscow), Roman Sharonov (Rubin Kazan), Vladimir Granat (Dynamo Moscow), Kirill Nababkin (CSKA Moscow).
Midfielders: Igor Denisov (Zenit St Petersburg), Roman Shirokov (Zenit St Petersburg), Konstantin Zyryanov (Zenit St Petersburg), Yuri Zhirkov (Anzhi Makhachkala), Alan Dzagoyev (CSKA Moscow), Igor Semshov (Dynamo Moscow), Denis Glushakov (Lokomotiv Moscow), Marat Izmailov (Sporting), Dmitry Kombarov (Spartak Moscow).
Forwards: Andrei Arshavin (Arsenal), Alexander Kerzhakov (Zenit St Petersburg), Roman Pavlyuchenko (Lokomotiv Moscow), Alexander Kokorin (Dynamo Moscow), Pavel Pogrebnyak (Fulham).
